Just a tip on the dock moving from monitor to monitor – this is most likely intended behaviour that you're triggering by accident. I agree with you, it's annoying, and it shouldn't work like this, but it does.

That being said – the dock will move between monitors if you take your mouse cursor and move it to the very bottom middle of a monitor and hold it there for a few seconds. If it's jumping from one monitor to the next, it's likely that you're triggering this accidentally in the course of doing something else. You can move the dock back to your intended monitor by doing the same deliberately on the monitor you want it to be on.